This invention relates to electrodes, and in particular to an electrode and method for locating the recurrent laryngeal nerve in a surgery patient.
A quite serious and recurring problem for otolaryngologists is the post operative side effect of vocal cord paralysis following thyroid surgery. Even the best and most experienced surgeons, using the most sophisticated equipment heretofore available, encounter a substantial hazard that the recurrent laryngeal nerve will be severed, stretched or bruised during surgery on or about the thyroid gland. This surgical hazard is a result of several factors, including the fact that the recurrent laryngeal nerve lies just posterior to the most inferior portion of the thyroid gland, and is very small and delicate. Further, it is quite difficult to distinguish this nerve from the background tissue when the area about the thyroid gland is inflamed, as well as covered with blood following the initial incision. As the result of these aforementioned complications, the risk of vocal cord damage following thyroid surgery is very high, and also is quite serious in that it can result in the patient's complete loss of speech. Even if the laryngeal nerve has simply been stretched or bruised, the loss of speech may last for several months. In the unfortunate cases where the nerve is completely severed, the paralysis is permanent, and surgical attempts to repair the same have not yet proven successful.
Attempts to identify the recurrent laryngeal nerve by monitoring the human laryngeal musculature (voice box) by electromyography with indwelling needle electrodes have been successful but additional risk from this procedure has been discovered. The puncture of the laryngeal musculature with needle electrodes invariably causes some bleeding in the muscle. The risk of muscle damage from scarring, risk of possible abscess formation and the trauma of invasive needle monitoring itself has made this method impractical and useless as a routine clinical technique.